A conventional cotton harvester includes two or more harvesting units arranged in side-by-side order at a front end of the harvester. Each harvesting unit typically includes a pair of picker rotors and a pair of doffer assemblies arranged in a complementary relationship with each other within a housing assembly.
Each picker rotor of a harvesting unit includes a plurality of vertically spaced rows of picker spindles. The picker spindles are systematically inserted into a row of cotton plants to entwine or snag cotton from the plants. The picking spindles, with the cotton wound thereon, are then led out of the path of the cotton plants to a doffer station defined by the respective doffer assembly. At the doffer station, the doffer assembly removes or strips the cotton from the spindles. The doffed cotton flows into a conventional cotton conveying structure which directs the cotton away from the harvesting unit.
A typical doffer assembly is rotatably arranged within the housing assembly of the harvesting unit adjacent to a picker rotor and includes a doffer unit and a drive unit. Both the doffer and drive units are provided with a vertical shaft. Flanged ends of the respective vertical shafts are secured to each other intermediate opposite ends of the doffer assembly. The flanged shaft ends are typically secured together by a series of circumferentially spaced releasable fasteners such as bolts or the like.
The doffer unit of each doffer assembly typically includes a series or stack of vertically spaced doffer elements or pads. The doffer pads are intermeshed with the rows of picker spindles and are in closely spaced substantially parallel relationship therewith so that they sweep over the spindles to dislodge the cotton therefrom. The doffer pads are typically formed of rubber, or a like elastomeric material, and during use they gradually wear away.
The proper spacial relationship between the doffer pads and the picker spindles is critical for proper performance of the harvesting unit. In most field conditions, the doffer assembly is vertically positioned through adjustment of the drive unit and such that the doffer pads just touch the picker spindle surface for proper removal of harvested cotton therefrom. Some field conditions, however, may require an interference between the doffer pad and the picker spindle surface to effect complete doffing of the cotton and maximized performance of the picking operation. The relationship between the doffer pads and the picker spindle surface changes in a short time period as the doffer pads wear away on the surface of the spindles and the contact or interference setting is lost. If the doffer assembly is not adjusted to vertically reposition the doffer pads, the picker spindles will wrap with cotton lint and lose their affinity for cotton thereby adversely effecting the picking operation.
Conventional doffer assemblies allow for periodic adjustment by the operator to accommodate for wear of the doffer pads. It has heretofore been known to provide the drive unit with a screw-type adjustment arrangement to manually move the doffer unit in a vertical direction to vertically position or locate the doffer pads relative to the picker spindles. To provide access thereto, the adjustment arrangement usually projects upwardly from the housing. Albeit provides access, the upwardly projecting adjustment arrangement mechanically and visually clutters the top surface of the harvesting unit and exposes the components of the adjustment arrangement to the ambient environment in which the harvester is operated. Accordingly, the screw-type adjusting arrangement is subject to corrosion, dust, dirt and other contaminants which complicate and encumber adjustment of the doffer assembly. Adding a protective cap to cover the screw-type adjustment mechanism only further complicates and makes the adjustment more tedious and difficult especially during a period when picking time is a premium concern of the operator.
Although adjustable to compensate for doffer wear, conventional doffer assemblies can be adjusted within only a limited range. Eventually, the extended wear on the doffer pads mandates replacement of the doffer unit. Notwithstanding the necessity, replacement of the doffer unit is a tedious, difficult and laborious process. The problem with replacing the doffer unit is accentuated by a lack of both visual and physical access to the fasteners which secure the flanged ends of the drive unit and doffer unit to each other. As will be understood, the housing assembly in which the doffer unit is rotatably arranged offers only limited space in which the operator is permitted to work. The intermeshed, closely spaced and substantially parallel relationship of the doffer pads with the picker spindles further complicates removal of the doffer unit from the picker housing.
The vertical axis about which the doffer assembly rotates is substantially parallel to the vertical axis of an adjacent picker rotor. A lower end of the doffer assembly is supported on a cantilevered doffer support. If the doffer support becomes tipped, the parallel relationship between the doffer assembly and the picker unit will be offset resulting in uneven wear on the doffer pads and spaces defined between the doffer pads and spindles resulting in incomplete doffing of the cotton from the spindles. According, a vertical support or post is arranged adjacent the doffer assembly and connected at its lower end to the doffer support. Although adding rigidity and strength to the doffer support, both the support post and cotton conveying structure extending from the housing assembly further complicate removal of the doffer assembly therefrom.
It is, therefore, desirable to provide a doffer assembly with a screw-type adjustment mechanism which readily facilitates adjustment of the spacial relationship between the doffer pads and the picker spindles and which is protected from the ambient environment in which the harvester operates. This would eliminate the dust, dirt and other corrosive elements from encumbering the adjustment mechanism and provide an improved aesthetic appearance for the harvesting unit. Moreover, the housing assembly and doffer assembly should be designed to enhance service accessibility thereto.